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Finding the Fourth Proportional to 115.84, 159.90 and 86.80

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Solution

The fourth proportional to 115.84, 159.90 and 86.80 is: 119.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    115.84 : 159.90 = 86.80 : x
  2. Step 2: Convert to fraction form
    115.84/159.90 = 86.80/x
  3. Step 3: Cross multiply
    115.84x = 159.90 × 86.80
  4. Step 4: Simplify right side
    115.84x = 13,879.32
  5. Step 5: Solve for x
    x = 13,879.32/115.84
  6. Step 6: Final answer
    x = 119.81

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.